Abstract: Thermal comfort has a great influence on the productivity and satisfaction of indoor building occupants. In some developing countries like Niger Republic, poverty and epileptic power supply are the twin problems impeding people from the use of refrigerated-based air conditioning systems to achieve thermal comfort. Also, the use of some refrigerants has adverse effect on the environment. Evaporative cooling systems are viable options for achieving thermal comfort especially in hot and dry climates. These systems, apart from their low cost and power requirement, they are environmentally friendly. This study attempts to determine the viability of using evaporative coolers to achieve thermal comfort in Niamey using the feasibility Index Model. The computed feasibility indices of Niamey in the months of January through December are -3.6, -4.4, -4.3, 2.8, 6.6, 11.2, 13.7, 17.0, 16.0, 9.8, 0.7 and -5.6 respectively. Employing the concept of the feasibility index (FI) model reveals that comfort cooling can be achieved in the months of January, February, March, April, May, October, November and December while relief cooling can be achieved in the months of June, July and September. The method also reveals the unsuitability of evaporative cooling in the month of August. Considering both the comfort and the relief cooling periods based on the FI model, evaporative coolers can therefore be a suitable alternative to refrigerated-base air conditioning systems.